We know less about life in the earth under our feet than we do about the far side of the moon. Yet every plant and animal you can think of depends on this vast hidden ecosystem.

Each shovel of soil holds more living things than all the human beings ever born. Lots of species are still waiting for scientists to identify and name them. This is a world where fungi lay traps for thread-like worms. Bacteria dine on toxic chemicals. The smaller the creature, the stranger are its habits.

Dig into this underground universe and meet its tiny but helpful residents.